New concept for the reduction of impurity scattering in remotely doped GaAs quantum wells

We present a new concept to reduce impurity scattering in remotely doped GaAs single quantum wells by using heavy-mass X electrons in barriers formed by short-period AlAs/GaAs superlattices to smooth the potential fluctuations of the ionized Si dopants. Electron mobilities as high as 120 m(2)/V s and electron densities up to 1.5 x 10(16) m(-2) are obtained in 10 nm GaAs single quantum wells in the one-subband conductivity mode without any parallel conductance. In addition to magnetotransport we present voltage dependent capacitance and photoluminescence measurements as well as self-consistent calculations to demonstrate the applicability of our concept.